Now here's a question I have asked several times at AOPA and EAA and never got an answer. Maybe these Bloggers can help me. Question: what's the influence of density altitude on hypoxia? We all learn that density altitude robs us of engine power, lift capacity, etc. Suppose that, on a warm/hot day, your 2000' MSL airport acts like it is at 5000'. So I 'loose' 3000'; also when the A/C's ceiling was normally, say 13000', it now will be 10000' (because the airplane 'thinks' or behaves like it is at 13000').
Back to the question: if I feel normally 'groggy', I mean in this case feeling the effects of hypoxia, at 13000', will I now feel the same at 10000'? If that is so, then all oxygen laws need to have this caveat included; example: use oxygen at 12500' under standard day conditions; change that altitude according the density altitude. I mean, if my engine can not 'breathe' anymore, the human body should respond the same, no? I repeat that I have asked this question to people like Barry Schiff, Jonathan Sackier, Rod Machado and others and I never got a direct response; the responses varied from "you are confusing pressure with density" (and if so, what's the effective difference?) to "interesting question; look for a future column on this", etc. Who can answer me with a real explicative answer? Thank you.